“It was so much fun to play someone who is so incredibly heightened. My character is a complete psychopath,” said Lively at the film’s premiere, held at the Museum of Modern Art in New York on Monday. “She’s so different than me. I don’t really swear, and I don’t drink. The whole experience was fun. I got to be a wild child.”

Lively, who arrived at the premiere with husband Ryan Reynolds, was thrilled to work with Feig on a genre-bending movie like this one. “He cranks these characters up, and makes them so over the top that it makes it comedic and funny,” she said. “I love that, because every day we had complete freedom to be emotional—to be over the top, funny, and to make bold choices. You don’t always get that. Sometimes you’re boxed in.”

Based on Darcey Bell’s popular 2017 novel, A Simple Favor (out September 14) centers on perky, type A, suburban-mommy vlogger Stephanie Smothers (Kendrick), who seeks to solve the sudden disappearance of her new friend, Emily Nelson (Lively). Emily vanishes after she asked Stephanie for a simple favor: to pick up her son from school one afternoon. Stephanie and Emily’s husband, Sean Townsend (Golding), set out to find where she has gone. The missing-person plot takes several warped twists and turns, keeping moviegoers off-balance as the mystery unfolds.

Golding, for one, said he was “gobsmacked” by that serpentine plot. “There are these moments where I was like, ‘This is insane!’ And there is a lot of potty-mouthed dialogue, and it comes from surprising areas.”

Kendrick, tasked with playing an overzealous parent who video-blogs about homemade gazpacho, also found the film demanding—especially when her character had to go up against Lively’s.

“O.K.—for real, it was a challenge,” the Oscar-nominated actress said on the carpet. “The character that I end up going head-to-head with is a very strong, beautiful woman, and my character is lonely, and she’s awkward, and doesn’t always say the right thing. So I tried to show her humanity as much as I could, because normally if I’m in a situation where I’m up against a 5-foot-10-inch blonde who’s beautiful, well dressed, and wealthy, I rely on wit and my sense of humor. And that wasn’t something that I could rely on with Stephanie. So I really had to dig deep and find the ways that I could show you that she’s been through trauma, and behaves in ways that are off-putting because she’s trying to cover the darkness that she feels inside of her. It was a lot of emotional work, but it was really fun. And it’s nice to have that kind of challenge.”

As Emily’s morally ambiguous husband, Golding upends expectations at every turn. It’s a role completely opposite from his lovable, swoon-inducing on-screen persona in Crazy Rich Asians.

“You’re kind of unsure if my character is good or bad,” said Golding. “That’s something that I want to continue—not just be stereotyped and be the heartthrob and romantic lead, but to play as diverse [of] characters as possible.”

Golding had finished Crazy Rich Asians, his first big-screen role, a mere two weeks before Feig contacted him about A Simple Favor. Feig had learned about Golding through his wife, a fan of the Crazy Rich Asians books who had been following news about the movie. “I watched all of Henry’s travel shows that he hosted, and I fell in love with him,” said Feig. “He’s so charming and so charismatic. And then I called Jon [M. Chu, who directed Crazy Rich Asians,] and asked, ‘Can he act?’ And he said, ‘He’s the best. He works so hard. He’s the nicest guy in the world.’ And I was like, ‘He’s in!’ Henry is a movie star that I have not seen in a long time. He’s a version of Cary Grant.”

Since the release of his first blockbuster, Golding’s life has changed dramatically. He’s getting recognized on the street, sitting in the front row at fashion shows, and enjoying the perks of fame—especially the special treatment he gets at airports.

“One time, I got picked up at L.A.X., and they have this special car that takes you from the plane on the tarmac directly to the other place where they collect your bags,” he revealed. “It was like a little strange look into the world of Crazy Rich Asians. I’m not used to that at all. That was a treat!”